P. Mo, Jiarong Chen, Chao Chen, Haiqing Qin, F. Lin
The PCBN (polycrystalline cubic boron nitride) composites were synthesized by mixing cubic boron nitride micropowders with Ti and Al micropowders at a certain mass ratio under high temperature and ultra-high pressure conditions. Phase composition and microstructure of the samples were analysed by X-ray diffraction and scanning electron microscopy. The effects of sintering temperature on the mechanical properties and microstructure of the PCBN ceramics were investigated. It was shown that BN, AlN, TiN and TiB2 phases coexist in the PCBN ceramics fabricated at ultra-high pressure (5.5GPa) and high temperature (1400-1500?C). With the increase of sintering temperature, pores and gaps inside the PCBN composites gradually disappeared and densified structure was formed. The best comprehensive mechanical properties of the PCBN composites were obtained at 1500 ?C with a flexural strength of 1009MPa and microhardness of 35.8GPa.
{"title":"Fabrication of polycrystalline cubic boron nitride composites under high pressure","authors":"P. Mo, Jiarong Chen, Chao Chen, Haiqing Qin, F. Lin","doi":"10.2298/pac2302157m","DOIUrl":"https://doi.org/10.2298/pac2302157m","url":null,"abstract":"The PCBN (polycrystalline cubic boron nitride) composites were synthesized by mixing cubic boron nitride micropowders with Ti and Al micropowders at a certain mass ratio under high temperature and ultra-high pressure conditions. Phase composition and microstructure of the samples were analysed by X-ray diffraction and scanning electron microscopy. The effects of sintering temperature on the mechanical properties and microstructure of the PCBN ceramics were investigated. It was shown that BN, AlN, TiN and TiB2 phases coexist in the PCBN ceramics fabricated at ultra-high pressure (5.5GPa) and high temperature (1400-1500?C). With the increase of sintering temperature, pores and gaps inside the PCBN composites gradually disappeared and densified structure was formed. The best comprehensive mechanical properties of the PCBN composites were obtained at 1500 ?C with a flexural strength of 1009MPa and microhardness of 35.8GPa.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68583341","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work, two series of BaTiO3-based ceramics, Ba1-xSrxTiO3 (x = 0, 0.2, 0.4, 0.6, 0.8) and BaTi1-xTaxO3 (x = 0.03, 0.06, 0.075, 0.09, 0.1), were synthesized by using standard solid-state reaction method at 1350 ?C, and then sintered at 1400 ?C for 10 h in air. Frequency-dependent dielectric and impedance properties were investigated at low temperature range of 100-300K. The changes in dielectric properties of the Ba1-xSrxTiO3 ceramics are believed to originate from the phase transition due to the different A-site Sr2+ doping concentration. The local electron-pinned defect-dipole effect is responsible for the enhancement of dielectric constant observed in the B-site Ta5+ doped BaTi1-xTaxO3 ceramics. The complex impedance analysis was used to discern the temperature and frequency dependence of grains and grain boundaries responses. The results suggest that A- and B-site doped BaTiO3 ceramics can be applied for different dielectric devices at low temperatures.
{"title":"Low-temperature dielectric and impedance properties of Ba1-xSrxTiO3 and BaTi1-xTaxO3 ceramics","authors":"Depeng Wang, Ruifeng Niu, Liqi Cui, Weitian Wang","doi":"10.2298/pac2303286w","DOIUrl":"https://doi.org/10.2298/pac2303286w","url":null,"abstract":"In this work, two series of BaTiO3-based ceramics, Ba1-xSrxTiO3 (x = 0, 0.2, 0.4, 0.6, 0.8) and BaTi1-xTaxO3 (x = 0.03, 0.06, 0.075, 0.09, 0.1), were synthesized by using standard solid-state reaction method at 1350 ?C, and then sintered at 1400 ?C for 10 h in air. Frequency-dependent dielectric and impedance properties were investigated at low temperature range of 100-300K. The changes in dielectric properties of the Ba1-xSrxTiO3 ceramics are believed to originate from the phase transition due to the different A-site Sr2+ doping concentration. The local electron-pinned defect-dipole effect is responsible for the enhancement of dielectric constant observed in the B-site Ta5+ doped BaTi1-xTaxO3 ceramics. The complex impedance analysis was used to discern the temperature and frequency dependence of grains and grain boundaries responses. The results suggest that A- and B-site doped BaTiO3 ceramics can be applied for different dielectric devices at low temperatures.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"131 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135311324","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Beichen Gao, Weinila Abulaiti, Zheng Guan, Limeng Liu
Although significant increase in mechanical properties has been achieved in ?-SiAlON ceramics by introducing self-toughening bimodal microstructure, the bimodal microstructure may not always result in better cutting performance of ?-SiAlON tool inserts. Herein Dy-?-SiAlON ceramics were prepared by hot-pressing at 1900?C under 30MPa. Diameter and aspect ratio of the large elongated ?-SiAlON grains pivotal to formation of bimodal microstructures were regulated by using 0-5wt.% Dy2O3 as a sintering additive. Mechanical properties and cutting performance of ?-SiAlON tool inserts were evaluated. The results showed good Vickers hardness (19.0-19.7GPa) and fracture toughness (3.61-4.18MPa?m1/2) increasing with crack propagation length. However, transverse section of the large elongated grains was revealed as critical crack to cause premature fracture of the ?-SiAlON ceramics. Fracture rather than attrition wear was recognized as dominant mechanism for tool failure, indicating that for better cutting performance of the ?-SiAlON tool inserts a selftoughening microstructure consisting of thinner grains with large aspect ratio is required.
{"title":"Effect of grain growth in bimodal microstructure on cutting performance of self-toughening Dy-α-SiAlON ceramic tool inserts","authors":"Beichen Gao, Weinila Abulaiti, Zheng Guan, Limeng Liu","doi":"10.2298/pac2303321g","DOIUrl":"https://doi.org/10.2298/pac2303321g","url":null,"abstract":"Although significant increase in mechanical properties has been achieved in ?-SiAlON ceramics by introducing self-toughening bimodal microstructure, the bimodal microstructure may not always result in better cutting performance of ?-SiAlON tool inserts. Herein Dy-?-SiAlON ceramics were prepared by hot-pressing at 1900?C under 30MPa. Diameter and aspect ratio of the large elongated ?-SiAlON grains pivotal to formation of bimodal microstructures were regulated by using 0-5wt.% Dy2O3 as a sintering additive. Mechanical properties and cutting performance of ?-SiAlON tool inserts were evaluated. The results showed good Vickers hardness (19.0-19.7GPa) and fracture toughness (3.61-4.18MPa?m1/2) increasing with crack propagation length. However, transverse section of the large elongated grains was revealed as critical crack to cause premature fracture of the ?-SiAlON ceramics. Fracture rather than attrition wear was recognized as dominant mechanism for tool failure, indicating that for better cutting performance of the ?-SiAlON tool inserts a selftoughening microstructure consisting of thinner grains with large aspect ratio is required.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135312345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chuanbo Zhang, Z. Tong, Congcong Xu, Jiaxing Wang, Zhiheng Jia
Stainless-steel slag was used to prepare glass-ceramics, which could solidify chromium (Cr) in the slag. The migration and distribution state of chromium in the slag during the preparation of the glass-ceramics have a great influence on the chromium fixation ability of the glass-ceramics. In this paper, the effects of Al2O3 content in the glass-ceramics on the migration and distribution of chromium during the nucleation and crystallization steps, and on the chromium fixation effect of the glass-ceramics were systematically studied. The results show that in the nucleation stage, with the increase of Al2O3 content, the number of chromium spinel (Cr-spinel) nanocrystals formed in the glass first increases and then decreases, and Cr in the glass phase gradually migrates to Cr-spinel nanocrystals. TEM and XPS analyses show that during crystallization, part of Cr in Cr-spinel diffuses into diopside lattice, and the other part of Cr still exists in Cr-spinel wrapped by diopside. Cr in the glass phase also diffuses and migrates into the diopside lattice with the formation of diopside crystals. The optimal Al2O3 content is 11.8wt.%, which results in 97.94wt.% of the total Cr being fixed in the diopside crystalline phase. The ability of chromium fixation is very high giving a very low Cr leaching concentration of 0.004mg/l. The research results provide theoretical and technical support for increased chromium fixation and realizing harmless and high-value utilization of stainless-steel slag.
{"title":"Effect of Al2O3 on migration and distribution of chromium and chromium fixation effect in stainless-steel slag glass-ceramics","authors":"Chuanbo Zhang, Z. Tong, Congcong Xu, Jiaxing Wang, Zhiheng Jia","doi":"10.2298/pac2301070z","DOIUrl":"https://doi.org/10.2298/pac2301070z","url":null,"abstract":"Stainless-steel slag was used to prepare glass-ceramics, which could solidify chromium (Cr) in the slag. The migration and distribution state of chromium in the slag during the preparation of the glass-ceramics have a great influence on the chromium fixation ability of the glass-ceramics. In this paper, the effects of Al2O3 content in the glass-ceramics on the migration and distribution of chromium during the nucleation and crystallization steps, and on the chromium fixation effect of the glass-ceramics were systematically studied. The results show that in the nucleation stage, with the increase of Al2O3 content, the number of chromium spinel (Cr-spinel) nanocrystals formed in the glass first increases and then decreases, and Cr in the glass phase gradually migrates to Cr-spinel nanocrystals. TEM and XPS analyses show that during crystallization, part of Cr in Cr-spinel diffuses into diopside lattice, and the other part of Cr still exists in Cr-spinel wrapped by diopside. Cr in the glass phase also diffuses and migrates into the diopside lattice with the formation of diopside crystals. The optimal Al2O3 content is 11.8wt.%, which results in 97.94wt.% of the total Cr being fixed in the diopside crystalline phase. The ability of chromium fixation is very high giving a very low Cr leaching concentration of 0.004mg/l. The research results provide theoretical and technical support for increased chromium fixation and realizing harmless and high-value utilization of stainless-steel slag.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68582840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
I. Sugihartono, B. Soegijono, E. Handoko, T. Tiam, A. Umar
La-doped ZnO (with 0, 1, 5 and 7 wt.% La) thin films were deposited on Si substrates by ultrasonic spray pyrolysis, using frequency of 1.7MHz, and heated at 450?C for 15min. The effect of La addition on the structural and optical properties of ZnO thin films was analysed. X-ray diffraction patterns confirmed that all prepared thin films had a polycrystalline hexagonal wurtzite structure with highly preferred texture in the (002) plane in the case of the ZnO containing 7 wt.% La. Atomic force microscopy analyses confirmed that the surface morphology is affected by La addition and the root mean square (RMS) roughness tended to be higher by increasing La content. The optical band gap energies of the La-doped thin films are smaller than that of the undoped ZnO. The photoluminescence properties of the prepared thin films confirmed that there was a significant redshift of DLE to wavelength of 711 nm when 1wt.% of La was incorporated in ZnO structure. It was proposed that the incorporation of La into the ZnO structure caused the oxygen atoms to have a strong bond with La.
{"title":"Structure and optical properties of La-doped ZnO thin films at room temperature","authors":"I. Sugihartono, B. Soegijono, E. Handoko, T. Tiam, A. Umar","doi":"10.2298/pac2302107s","DOIUrl":"https://doi.org/10.2298/pac2302107s","url":null,"abstract":"La-doped ZnO (with 0, 1, 5 and 7 wt.% La) thin films were deposited on Si substrates by ultrasonic spray pyrolysis, using frequency of 1.7MHz, and heated at 450?C for 15min. The effect of La addition on the structural and optical properties of ZnO thin films was analysed. X-ray diffraction patterns confirmed that all prepared thin films had a polycrystalline hexagonal wurtzite structure with highly preferred texture in the (002) plane in the case of the ZnO containing 7 wt.% La. Atomic force microscopy analyses confirmed that the surface morphology is affected by La addition and the root mean square (RMS) roughness tended to be higher by increasing La content. The optical band gap energies of the La-doped thin films are smaller than that of the undoped ZnO. The photoluminescence properties of the prepared thin films confirmed that there was a significant redshift of DLE to wavelength of 711 nm when 1wt.% of La was incorporated in ZnO structure. It was proposed that the incorporation of La into the ZnO structure caused the oxygen atoms to have a strong bond with La.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68583222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Matović, J. Maletaskic, V. Maksimović, J. Zagorac, Aleksandar Luković, Yuping Zeng, I. Cvijović-Alagić
A novel class of high-entropy pyrochlore compounds with multiple elements at the A and B site positions (A2B2O7) was successfully obtained. Powders with (La1/7Sm1/7Nd1/7Pr1/7Y1/7Gd1/7Yb1/7)2(Sn1/3Hf1/3Zr1/3)2O7 nominal composition were fabricated from pure metal oxides obtained through a reaction of metal nitrates (for site A) and metal chlorides (for site B) with sodium hydroxide during the solid-state displacement reaction (SSDR). The phase evolution was analyzed using XRD method. During the thermal treatment of ten individual metal oxides, the single pyrochlore phase was created. The present study showed that the highdensity (98%TD) ceramics with a hardness of 8.1GPa was successfully obtained after pressureless sintering at 1650 ?C for 4 h. Results of the Raman study and the Rietveld structural refinement showed that sintered highentropy ceramics is characterized by a single-phase pyrochlore structure, which was investigated in detail.
{"title":"Heavily doped high-entropy A2B2O7 pyrochlore","authors":"B. Matović, J. Maletaskic, V. Maksimović, J. Zagorac, Aleksandar Luković, Yuping Zeng, I. Cvijović-Alagić","doi":"10.2298/pac2302113m","DOIUrl":"https://doi.org/10.2298/pac2302113m","url":null,"abstract":"A novel class of high-entropy pyrochlore compounds with multiple elements at the A and B site positions (A2B2O7) was successfully obtained. Powders with (La1/7Sm1/7Nd1/7Pr1/7Y1/7Gd1/7Yb1/7)2(Sn1/3Hf1/3Zr1/3)2O7 nominal composition were fabricated from pure metal oxides obtained through a reaction of metal nitrates (for site A) and metal chlorides (for site B) with sodium hydroxide during the solid-state displacement reaction (SSDR). The phase evolution was analyzed using XRD method. During the thermal treatment of ten individual metal oxides, the single pyrochlore phase was created. The present study showed that the highdensity (98%TD) ceramics with a hardness of 8.1GPa was successfully obtained after pressureless sintering at 1650 ?C for 4 h. Results of the Raman study and the Rietveld structural refinement showed that sintered highentropy ceramics is characterized by a single-phase pyrochlore structure, which was investigated in detail.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68583307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this research, SiC ceramics were densified via spark plasma sintering (SPS) with 0.5wt.% B4C and 1.5wt.% C additions at temperatures ranging from 1900 to 2000?C for 5-65min under 10-50MPa applied pressure with an intermediate dwell at 1400?C, and the effects of applied pressure, sintering temperature, and dwelling time were examined. The samples sintered under 50MPa applied pressure had high density (>99%), and showed high elastic modulus (~420MPa). However, lower applied pressure caused a decrease in density and elastic properties. The increase of sintering temperature from 1900 to 2000?C, while sintering time and pressure remained the same, caused grains coarsening. Increasing the dwelling time for the samples sintered at 1900 and 2000?C showed that sintering at a relatively lower temperature for a longer period of time did not increase grain size significantly. On the other hand, increasing the dwelling time at 2000?C caused excessive grain growth. The results show that fine-grained highly dense SiC can be produced by spark plasma sintering at 1900?C for 5min under 50MPa.
{"title":"Investigation of the effect of pressure, sintering temperature and time on silicon carbide microstructure","authors":"Z. Yaşar, V. Delucca, R. Haber","doi":"10.2298/pac2302189y","DOIUrl":"https://doi.org/10.2298/pac2302189y","url":null,"abstract":"In this research, SiC ceramics were densified via spark plasma sintering (SPS) with 0.5wt.% B4C and 1.5wt.% C additions at temperatures ranging from 1900 to 2000?C for 5-65min under 10-50MPa applied pressure with an intermediate dwell at 1400?C, and the effects of applied pressure, sintering temperature, and dwelling time were examined. The samples sintered under 50MPa applied pressure had high density (>99%), and showed high elastic modulus (~420MPa). However, lower applied pressure caused a decrease in density and elastic properties. The increase of sintering temperature from 1900 to 2000?C, while sintering time and pressure remained the same, caused grains coarsening. Increasing the dwelling time for the samples sintered at 1900 and 2000?C showed that sintering at a relatively lower temperature for a longer period of time did not increase grain size significantly. On the other hand, increasing the dwelling time at 2000?C caused excessive grain growth. The results show that fine-grained highly dense SiC can be produced by spark plasma sintering at 1900?C for 5min under 50MPa.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68583417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kirti Pasupuleti, Kevin Vattappara, Sylvester Gomes, Parvati Ramaswamy
La2Zr2O7, La2(Zr0.7Ce0.3)2O7 and La2Ce2O7 pyrochlore plasma sprayable powders were synthesized and plasma spray coated on steel plates with NiCrAlY bond coat. Three different configurations were used: duplex, multilayer functionally graded and multilayer, with different combinations of commercial 8% yttria stabilized zirconia (8YSZ) and NiCrAlY (bond coat) layers. The prepared coatings were compared with the standard duplex 8YSZ thermal barrier coatings (TBCs) with a goal to study their suitability to serve as TBCs. TBCs? layer thicknesses and interfaces were studied via SEM on polished cross section metallographic samples removed from the spray coated TBCs. Thermal fatigue resistance was evaluated by directing a gas flame on the ceramic surface at 1200 and 1400 ?C, followed by its rapid withdrawal and forced cooling by pedestal fan. The maximum number of thermal shock cycles the coatings could withstand before failure was determined. The multilayered TBCs with lanthanum cerate composition stacked with 8YSZ exhibited the superior thermal fatigue resistance characteristics compared to all other studied TBCs. The findings were correlated with the crystalline phases of the ceramic coatings, obtained via XRD, and discussed in the light of existing literature.
{"title":"Thermal fatigue characteristics of 8Y2O3-ZrO2, La2Zr2O7, La2(Zr0.7Ce0.3)2O7 and La2Ce2O7 thermal barrier coatings in duplex, multilayer functionally graded and multilayer configurations","authors":"Kirti Pasupuleti, Kevin Vattappara, Sylvester Gomes, Parvati Ramaswamy","doi":"10.2298/pac2303236p","DOIUrl":"https://doi.org/10.2298/pac2303236p","url":null,"abstract":"La2Zr2O7, La2(Zr0.7Ce0.3)2O7 and La2Ce2O7 pyrochlore plasma sprayable powders were synthesized and plasma spray coated on steel plates with NiCrAlY bond coat. Three different configurations were used: duplex, multilayer functionally graded and multilayer, with different combinations of commercial 8% yttria stabilized zirconia (8YSZ) and NiCrAlY (bond coat) layers. The prepared coatings were compared with the standard duplex 8YSZ thermal barrier coatings (TBCs) with a goal to study their suitability to serve as TBCs. TBCs? layer thicknesses and interfaces were studied via SEM on polished cross section metallographic samples removed from the spray coated TBCs. Thermal fatigue resistance was evaluated by directing a gas flame on the ceramic surface at 1200 and 1400 ?C, followed by its rapid withdrawal and forced cooling by pedestal fan. The maximum number of thermal shock cycles the coatings could withstand before failure was determined. The multilayered TBCs with lanthanum cerate composition stacked with 8YSZ exhibited the superior thermal fatigue resistance characteristics compared to all other studied TBCs. The findings were correlated with the crystalline phases of the ceramic coatings, obtained via XRD, and discussed in the light of existing literature.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"139 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135263530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Tian, Minzheng Zhu, Lingbo Shao, Xiaoling Qu, Lejie Zhu, Chao Chen, Caoli Wang, Yang Liu
Yttrium and aluminium co-substitutions on lanthanum molybdate ceramics with the nominal formula La1.75Y0.25Mo2-xAlxO9-?? (LYMA, x = 0, 0.1, 0.2, 0.3 and 0.4) were synthesized by citric acid-nitrate combustion method and used for preparation of solid electrolyte for intermediate-temperature solid oxide fuel cells (ITSOFCs). Phase composition, structure, conductivity and electrical properties of LYMA have been investigated as a function of aluminium content by X-ray diffraction, scanning electron microscopy and electrochemical impedance spectroscopy, respectively. Experimental results showed that the substitution of La and Mo with appropriate amounts of Y and Al can effectively stabilize the ?-form of La2Mo2O9 at room temperature and inhibit its phase transition to ?-form. The LYMA synthesized by combustion method exhibited a better sinterability where relative density of the samples sintered at 950?C for 4 h was higher than 95%TD. The performance of the LYMA electrolyte was found to be related to Al-content. The La1.75Y0.25Mo1.8Al0.2O8.7 exhibited high oxide ion conductivity (?= 42mS/cm at 800?C) and low electrical activation energy (Ea = 1.18 eV). These preliminary results indicate that the LYMA is a promising electrolyte for IT-SOFCs.
标称配方为La1.75Y0.25Mo2-xAlxO9-?的钼酸镧陶瓷上钇铝共取代(LYMA, x = 0, 0.1, 0.2, 0.3和0.4))采用柠檬酸-硝酸盐燃烧法合成，用于制备中温固体氧化物燃料电池(itsofc)的固体电解质。利用x射线衍射、扫描电镜和电化学阻抗谱分别研究了LYMA的相组成、结构、电导率和电性能与铝含量的关系。实验结果表明，用适量的Y和Al取代La和Mo可以在室温下有效地稳定La2Mo2O9的?-形态，抑制其向?-形态的相变。燃烧法合成的LYMA具有较好的烧结性能，烧结样品的相对密度为950?4 h C高于95%TD。LYMA电解液的性能与al含量有关。La1.75Y0.25Mo1.8Al0.2O8.7具有较高的氧化离子电导率(?= 42mS/cm(800℃)，电活化能低(Ea = 1.18 eV)。这些初步结果表明，LYMA是一种很有前途的it - sofc电解质。
{"title":"Preparation and characterization of La1.75Y0.25Mo2-xAlxO9-δ as solid electrolyte for intermediate temperatures SOFC","authors":"C. Tian, Minzheng Zhu, Lingbo Shao, Xiaoling Qu, Lejie Zhu, Chao Chen, Caoli Wang, Yang Liu","doi":"10.2298/pac2301031t","DOIUrl":"https://doi.org/10.2298/pac2301031t","url":null,"abstract":"Yttrium and aluminium co-substitutions on lanthanum molybdate ceramics with the nominal formula La1.75Y0.25Mo2-xAlxO9-?? (LYMA, x = 0, 0.1, 0.2, 0.3 and 0.4) were synthesized by citric acid-nitrate combustion method and used for preparation of solid electrolyte for intermediate-temperature solid oxide fuel cells (ITSOFCs). Phase composition, structure, conductivity and electrical properties of LYMA have been investigated as a function of aluminium content by X-ray diffraction, scanning electron microscopy and electrochemical impedance spectroscopy, respectively. Experimental results showed that the substitution of La and Mo with appropriate amounts of Y and Al can effectively stabilize the ?-form of La2Mo2O9 at room temperature and inhibit its phase transition to ?-form. The LYMA synthesized by combustion method exhibited a better sinterability where relative density of the samples sintered at 950?C for 4 h was higher than 95%TD. The performance of the LYMA electrolyte was found to be related to Al-content. The La1.75Y0.25Mo1.8Al0.2O8.7 exhibited high oxide ion conductivity (?= 42mS/cm at 800?C) and low electrical activation energy (Ea = 1.18 eV). These preliminary results indicate that the LYMA is a promising electrolyte for IT-SOFCs.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68582686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tao Wang, Jianmin Liu, Feng Jiang, Guo Feng, Jianye Liang, L. Miao, Qian Wu, Xinbin Lao, Mengting Liu, Weihui Jiang
A new approach was developed to prepare NaZr2(PO4)3 (NZP) powders at low temperature of 330?C. The effect of different molar ratios of ZrO(NO3)2 ? xH2O to NaH2PO4 ? 2H2O on the synthesis of NZP powders was systematically investigated by XRD, FE-SEM, TEM, EDS and Raman spectroscopy. The mineralizer NaNO3 was formed in situ due to the mechanochemical reaction between raw materials ZrO(NO3)2 ? xH2O and NaH2PO4 ? 2H2O during the grinding process. When the optimal molar ratio of Zr:P = 2:6 was used, the NZP powders with high crystallinity, good dispersity and particle sizes in the range of 500-700 nm were obtained. The dense NZP ceramics was obtained by sintering at 1100 ?C for 3 h with 2 wt.% ZnO as the sintering aid. The relative density and Vickers hardness of the sintered ceramics reached 93.4% and 704MPa, respectively.
{"title":"Low temperature synthesis of NaSICON NaZr2(PO4)3 powders with the assistance of in situ formed mineralizer","authors":"Tao Wang, Jianmin Liu, Feng Jiang, Guo Feng, Jianye Liang, L. Miao, Qian Wu, Xinbin Lao, Mengting Liu, Weihui Jiang","doi":"10.2298/pac2302140w","DOIUrl":"https://doi.org/10.2298/pac2302140w","url":null,"abstract":"A new approach was developed to prepare NaZr2(PO4)3 (NZP) powders at low temperature of 330?C. The effect of different molar ratios of ZrO(NO3)2 ? xH2O to NaH2PO4 ? 2H2O on the synthesis of NZP powders was systematically investigated by XRD, FE-SEM, TEM, EDS and Raman spectroscopy. The mineralizer NaNO3 was formed in situ due to the mechanochemical reaction between raw materials ZrO(NO3)2 ? xH2O and NaH2PO4 ? 2H2O during the grinding process. When the optimal molar ratio of Zr:P = 2:6 was used, the NZP powders with high crystallinity, good dispersity and particle sizes in the range of 500-700 nm were obtained. The dense NZP ceramics was obtained by sintering at 1100 ?C for 3 h with 2 wt.% ZnO as the sintering aid. The relative density and Vickers hardness of the sintered ceramics reached 93.4% and 704MPa, respectively.","PeriodicalId":20596,"journal":{"name":"Processing and Application of Ceramics","volume":"1 1","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68583114","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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